IMAPS: Can't connect to mx.domain.com

[wooch]

I have OTRS 5.0.14, Exchange 2013 and I'm using IMAPS to fetching mail.
Every day I receive that messages on /var/log/otrs.log:

[Mon Nov 7 08:38:13 2016][Error][Kernel::System::Daemon::DaemonModules::BaseTaskWorker::_HandleError][51] There was an error executing Execute() in Kernel::System::Console::Command::Maint::PostMaster::MailAccountFetch: ERROR: OTRS-otrs.Console.pl-Maint::PostMaster::MailAccountFetch-83 Perl: 5.16.3 OS: linux Time: Mon Nov 7 08:38:13 2016

Message: IMAPS: Can't connect to mx.domain.com

Traceback (45435):
Module: Kernel::System::MailAccount::IMAP::_Fetch Line: 142
Module: Kernel::System::MailAccount::IMAP::Fetch Line: 86
Module: Kernel::System::MailAccount::MailAccountFetch Line: 440
Module: Kernel::System::Console::Command::Maint::PostMaster::MailAccountFetch::Run Line: 94
Module: (eval) Line: 460
Module: Kernel::System::Console::BaseCommand::Execute Line: 454
Module: (eval) Line: 150
Module: Kernel::System::Daemon::DaemonModules::SchedulerTaskWorker::Cron::Run Line: 129
Module: Kernel::System::Daemon::DaemonModules::SchedulerTaskWorker::Run Line: 250
Module: (eval) Line: 316
Module: main::Start Line: 316
Module: /opt/otrs/bin/otrs.Daemon.pl Line: 138

These messages appear randomly, 15-20 times a day, meanwhile mail flows correctly(I think so...) I get report about this error every time by e-mail. There are no errors on Exchange side.
I can't realize what the problem is it? Can you help me?

[wurzel]

Hi,

Message: IMAPS: Can't connect to mx.domain.com

Your connection can not be establishes.

Maybe you are asking too often or response times are slow.
Or Your DNS is not working properly. You are using a Exchange Cluster?

Seems to be a network issue

Flo

[wooch]

Hi,
I asking every 5 minutes, but these errors usually appear between requests.
DNS is working correctly and, yes, I'm using Exchange cluster with balancing via DNS round-robin.

[wurzel]

Hi,

hard to say where the problem is.

it could be the load balancer doing wrong things

Flo

[wooch]

Hi
It seems to be that your were right,
I've investigated that some IMAPS settings on my Exchange servers were different.
So I receive only 1 message for 2-3 days now.
Thanx.